It's kind of in between in my opinion. You can kind of watch without knowing UC since most of the main characters are a new generation (Banagher, Audrey/Mineva, etc.), but yeah the more you know certainly helps you get in quicker like knowing the factions, who Char was, etc.
Yeah, it's definitely 80's hair.
Nah, this takes place 3 years after the Char's Counterattack movie (UC0093).